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Modern Geomatics Technologies and Applications

                As we know the temporal changes of the Earth’s gravity field can be observed on a global scale
         with low–low satellite-to-satellite tracking (SST) missions. Therefore, for a better understanding of the
         faults, earthquake mechanisms and physics of the interior of the earth should be studied. In order to do so,
         we should improve our knowledge of the earth mechanism and its gravity field. Because of the limitations
         of measuring instruments and impossibility of collecting data from the entire surface of the Earth, Our
         knowledge  of  the  Earth’s  gravity  field  is  incomplete.  Besides,  to  benefit  from  more  fruitful  studies,
         periodic, global and homogeneous data collection is a must. Therefore, we need satellites with better orbits
         and lower heights.
                For this purpose, three satellites by the names of CHAMP (CHAllenging Mini satellite Payload) in
         2000, GRACE (Gravity  Recovery and Climate Experiment) in 2002 and GOCE (Gravity recovery and
         steady-state Ocean Circulation Explorer) in 2004 were lunched. All of the scenarios had low and nearly
         polar orbit. They collect data continuously and in a three-dimensional format. All of these scenarios can
         separate  non-gravitational  from  gravitational  signal  parts.  In  the  scenarios  with  pair  satellite  (like
         GRACE),  inter-satellite  distance  changes  are  tracked  and  in  the  scenarios  with  single  satellite  (like
         GOCE), the gravity gradiometry is checked. Accordingly, the final gravity signal is achieved Rummel et
         al. (2002).
                Through  development  of  space  geodetic  techniques  such  as  the  satellite  gravity  missions,
         coseismic gravity changes can be detected from space. The coseismic gravity change caused by the 2004
         Sumatra earthquake was detected by GRACE Sun and Okubo (2004) and Han et al. (2006). The gravity
         changes caused by the earthquake were calculated and interpreted by using a very simple method based on
         a half-space earth model Han et al. (2006).
                During the past two decades, satellite gravity (CHAMP, GRACE and GOCE) missions increased
         the accuracy, spatial resolution, and temporal resolution of the Earth’s gravity potential models Elsaka et
         al. (2014). In the future, we may have access to improved data if better scenarios are launched in different
         configuration of formations. In order to obtain optimum scenarios different studies were published during
         the last decades and they are all included in Elsaka et al. (2014). All of them reveal a substantial increase
         in accuracy and sensitivity.
                After  Sumatra-Andaman  earthquake  and  analysis  of  GRACE  data,  it  was  found  out  that  using
         GRACE data to detect coseismic effects was possible [e.g., (Cambiotti and Sabadini, 2012, Chen et al.,
         2007, Dai et al., 2014, Han et al., 2006, Han et al., 2013, Han et al., 2010, Han et al., 2011, Heki and
         Matsuo,  2010,  Matsuo  and  Heki,  2011,  Wang  et  al.,  2012a,  Zhou  et  al.,  2012).  The  modern  geodetic
         techniques will enable us to have a better detection of the coseismic deformations such as displacement,
         gravity changes, etc. [e.g., (Chang and Chao, 2011, Hayes, 2011, Ito et al., 2011, Kobayashi et al., 2011,
         Li and Shen, 2015, Sato et al., 2011, Shao et al., 2011, Sleep, 2012, Suito et al., 2011, Suzuki et al., 2012,
         Han et al., 2006, Wang, 2012, Wang et al., 2012b)].
                The goal of this contribution is to focus on gravity satellites that sense earthquake signals in the
         best quality via alternative configuration scenarios applied in future gravimetric satellite missions. Full-
         scale simulations of various mission scenarios covering GRACE, GRACE-FO, Cartwheel, pendulum and
         Helix were performed. In this work, one more month was added to the simulated time span to analyse the
         simulated earthquake signals.
                This article is therefore interested in studying the sensitivity of satellite gravity scenarios to gravity
         changes caused by the Maule fault as the case study. The study is tested on real and hypothetical strike










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